Update maxVersion string (#45593)

Author: daxmc99

internal/database/migration/shared/upgradedata/cmd/generator/consts.go

@@ -9,7 +9,7 @@ import (
 // NOTE: This should be kept up-to-date with cmd/migrator/build.sh
 // so that we "bake in" fallback schemas everything we support migrating
 // to.
-const maxVersionString = "4.1.0"
+const maxVersionString = "4.3.0"
 
 // MaxVersion is the highest known released version at the time the migrator was built.
 var MaxVersion = func() oobmigration.Version {